Hard-metal composition



liYZlMilEi inf a,

sii-riuniti Y i Y m" KARL BGHBTIB, 0I BERLIN-LICHT, GERMANY, .ASBIGNOBI0 G mno conm, A @EPURATION or New roux. mii-armer. ooiirosirroir. inpraying. Application sisi 'prii es, 192s, sensi m. 104,618,

, My present' invention relates to metal coui-l positions and moreparticularly to compositions comprising hard metal curbides. It is oneof the objects of my invention to provide e herd metal composition ofvery greet strength and tenacity which is particularly adaptable for usein connection with weer resisting bodies und cutting tools.

In 'my prior Potent No. 1,549,615 grunted August il, 1925, l huyedescribed o iid claimed e. sintered bord motel composition formed byeddiiig to e powdered tungsten lesser degree of lisidness then theiuetel coimpositioiidescribed-in the potent but u much greater degree oftoughness or tenscity. ln the manufacture of tbe new product or mu-4terbil,- ll beve found it advantageous to curburizeftlie powdered 'iormof tbe besic motel employed, suoli us tungsten, in tbe presence oi theimpor of e hydrocarbon, suoli es methoiie, or tbe like although tbecerburizetion y muy be eiliected by mixing the tungmen powder withcarbon such as soot or sugerof carbon if desired. The resulting'composition, however, diii'ers Vstructurelly from that of the priorpatent mainly in tbe umount ot 2 suxiiiery instel employed.

ln making tbe new product, en auxiliary metal is applied to e, powderedherd motel carbide, such` es tungsten carbide for exemple, the auxiliarymetal buying esintering temperature below the melting point of thecarbide. The carbide is produced by liesting the tungsten powder toapproximately 1000* C. in the presence of. e. hydrocarbon vapor, such asmethane. i When produced in this manner the carbide is a looselyadherent mass which may be easily broken int/o small pieces by handwitlioutfthe em loyment of auxilio, l mechanical means. he carboncontentbf `the curbide will usually be substuntiallthess=xue-es'"described in the prior from 3 to10% 'zof the carbidepatent, t :itis i, Y A und muy tungsten monoendyin Germany Hay 7, 1035.

carbide to hen tbe carbide is prepared iii 1,121,416 "PATENT foi-Fi thismanner it is possible to use o, larger volume of the auxiliary metalthou wus employed iii the prior patent, The use ci ed-` ditionol'auxiliary motel provides u metal composition whicii possesses u highdegree of tenacity and lierdiiess although tbe hardness of the presentcomposition is slightly less than that described iii my prior potent.'lFiie increased teiiecity of the present composb tion, however,together with the bieb degree of hardness which is obteiiied melres ithighly desirable igor certain uses es in coii` section with cuttingtools und yurious forms of utensils. 4

Zilie ouiriiiziry metals muy comprise, es in ilic moin patent, motelswiiicli lieve e sistern iirg temperature lower tliuii tbe meltingpointof tbe cu-rbide, ioi' enuuipldiron, comit sindv nickel, und the quantityoit uuiiii iury metal employed muy constitute from l0 to 20% oit theslioy, ultliougli ordinerily it will not exceed 20% it un extremely bigbdegree oi' lisrdries is required.. Cutting tools formed of tlie uborecomposition ure extremely bord oud tough, und ure copoble oi cutting notonly the liurdest lmown steels but also materiels which generally ubrudecutting 'tools The eiiuiliury motel muy be in iiiiely powdered form undshould be "pressed into tbe sof pulverizeol bord metal carbide, und' theinold- I ed bod tben lieuted tou sintering tem ereture. he pressureemployed dependps ou the shape or tbe iiiiished product und muy verybetween 20@ und 800 lig. per sq. om. rllie resulting muteriul isinsgnetic, und itis my opinion tbut tbe suiiiliery metal sets .to cementtlie particles ot tbe carbide, giving strength und toughness to tlienislicd urticle. As' described iii my prior patent tlie temperature etwhich siiiteringV occurs is olif .footed by tbe quantity oit theauxiliary instel l employed but iii eny cese tbe presence of tbeauxiliary metal reduces the siiitering point of the body` for below thefusion fpoiut ot tlie carbide. or exemple, with 5 to 7%'75 cobelt. thefinal sintering temperature is about 14000 C. With 10% cobalt, thesintering temperature is 13.80 (Maud with 15%co-` halt, the sinteringtemperature .is 1340? G.

The sintering temperature should be maiii` tained more than one hour,

groferebly an hour `and a half, no ma-tter ow high the iin `cob-altcontent of the composition. *If desired, instead of a singleauxiliarymet'al a plurality of such metalsmay be employed but the amountof such metals should not` ordinaril exceed of the. entire quantity ofthe al oy.

I by Letters Patent of the United States isf--y CSI 1."A sintered, hardand tough, metal composition consisting mainly of a hard metal carbideand an auxiliary metal cementing particles of the carbide together, saidauX- iliary metal havin a sintering temperature lower than the me tingpoint of the carbide and comprising more than 10% of the re' sultingcombination.

2. Av `ntered, hard and tough, composi- .said auxiliary metal formingmore than 10% but not more than 20% of the total content of thecomposition, saidcomposition having a sintering temperature lower thanthe melting point of the carbide.

5. A sintered, hard and tough, metal composition consisting largely of ahard metal carbide, and' containing an appreciable amount of cobalt, thecobalt forming more ary What I claim as new and desire to' secureVcomposition. I 1

6. A sintered cutting tool, said tool le011- sisting mainly of a hardmetal carbide, and

containing an appreciable amount of auxilimetal having a sinteringtemperature lower than the melting point of the carbide, said auxiliarylmetal forming more than 10% of the total content of the cutting tool.

7. A sintered cutting tool consisting largely of a hard metal carbide,and containing an appreciable amount of cobalt, the cobalt forming morethan 10% of the total content of the cutting tool.

8. A sintered cutting tool consisting largely of a carbide of tungstenand containing an appreciable amount of a metal having a lower meltingpoint that the carbide, said metal forming more than 10% of the totalcontent of the cutting tool.

9. A sintered, hard and tough, metal composition consisting mainly oftungsten carbide and containing more than 10% of cobalt. i'

10. A. .sintered, hard and tough, metal composition consisting mainlyJot a carbide ot metal of the sixth group and a quantity of metal of theiron group, the metal ofthe iron group forming more than 10% and lessthan 20% of the composition. i

1l. AV sintered, hard and tough, metal composition consisting largely oftungsten and containing cobalt and carbon, the amount of cobalt beingmore than 10% and less than 20% of the total content of the metalcomposition.

KARL SCHRTER.

i than 10% of the total content of the metal

